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commit a39f009acefd85d3e36bcae828a4e67c9dce9684
parent 5bbf1b6d05337c02218f5f351258cd1bf31ffde5
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sat,  9 Mar 2019 09:02:47 -0800

Merge tag 'pstore-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore cleanups from Kees Cook:

 - Remove some needless memory allocations (Yue Hu, Kees Cook)

 - Add zero-length checks to avoid no-op calls (Yue Hu)

* tag 'pstore-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Avoid needless alloc during header write
  pstore/ram: Add kmsg hlen zero check to ramoops_pstore_write()
  pstore/ram: Move initialization earlier
  pstore: Avoid writing records with zero size
  pstore/ram: Replace dummy_data heap memory with stack memory

Diffstat:
Mfs/pstore/platform.c | 3+++
Mfs/pstore/ram.c | 64+++++++++++++++++++++++++++++-----------------------------------
2 files changed, 32 insertions(+), 35 deletions(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c @@ -501,6 +501,9 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c) { struct pstore_record record; + if (!c) + return; + pstore_record_init(&record, psinfo); record.type = PSTORE_TYPE_CONSOLE; diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c @@ -110,7 +110,6 @@ struct ramoops_context { }; static struct platform_device *dummy; -static struct ramoops_platform_data *dummy_data; static int ramoops_pstore_open(struct pstore_info *psi) { @@ -346,17 +345,15 @@ out: static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz, struct pstore_record *record) { - char *hdr; + char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */ size_t len; - hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n", + len = scnprintf(hdr, sizeof(hdr), + RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n", (time64_t)record->time.tv_sec, record->time.tv_nsec / 1000, record->compressed ? 'C' : 'D'); - WARN_ON_ONCE(!hdr); - len = hdr ? strlen(hdr) : 0; persistent_ram_write(prz, hdr, len); - kfree(hdr); return len; } @@ -424,6 +421,9 @@ static int notrace ramoops_pstore_write(struct pstore_record *record) /* Build header and append record contents. */ hlen = ramoops_write_kmsg_hdr(prz, record); + if (!hlen) + return -ENOMEM; + size = record->size; if (size + hlen > prz->buffer_size) size = prz->buffer_size - hlen; @@ -716,15 +716,6 @@ static int ramoops_probe(struct platform_device *pdev) phys_addr_t paddr; int err = -EINVAL; - if (dev_of_node(dev) && !pdata) { - pdata = &pdata_local; - memset(pdata, 0, sizeof(*pdata)); - - err = ramoops_parse_dt(pdev, pdata); - if (err < 0) - goto fail_out; - } - /* * Only a single ramoops area allowed at a time, so fail extra * probes. @@ -734,6 +725,15 @@ static int ramoops_probe(struct platform_device *pdev) goto fail_out; } + if (dev_of_node(dev) && !pdata) { + pdata = &pdata_local; + memset(pdata, 0, sizeof(*pdata)); + + err = ramoops_parse_dt(pdev, pdata); + if (err < 0) + goto fail_out; + } + /* Make sure we didn't get bogus platform data pointer. */ if (!pdata) { pr_err("NULL platform data\n"); @@ -892,13 +892,12 @@ static inline void ramoops_unregister_dummy(void) { platform_device_unregister(dummy); dummy = NULL; - - kfree(dummy_data); - dummy_data = NULL; } static void __init ramoops_register_dummy(void) { + struct ramoops_platform_data pdata; + /* * Prepare a dummy platform data structure to carry the module * parameters. If mem_size isn't set, then there are no module @@ -909,30 +908,25 @@ static void __init ramoops_register_dummy(void) pr_info("using module parameters\n"); - dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL); - if (!dummy_data) { - pr_info("could not allocate pdata\n"); - return; - } - - dummy_data->mem_size = mem_size; - dummy_data->mem_address = mem_address; - dummy_data->mem_type = mem_type; - dummy_data->record_size = record_size; - dummy_data->console_size = ramoops_console_size; - dummy_data->ftrace_size = ramoops_ftrace_size; - dummy_data->pmsg_size = ramoops_pmsg_size; - dummy_data->dump_oops = dump_oops; - dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU; + memset(&pdata, 0, sizeof(pdata)); + pdata.mem_size = mem_size; + pdata.mem_address = mem_address; + pdata.mem_type = mem_type; + pdata.record_size = record_size; + pdata.console_size = ramoops_console_size; + pdata.ftrace_size = ramoops_ftrace_size; + pdata.pmsg_size = ramoops_pmsg_size; + pdata.dump_oops = dump_oops; + pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU; /* * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC * (using 1 byte for ECC isn't much of use anyway). */ - dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc; + pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc; dummy = platform_device_register_data(NULL, "ramoops", -1, - dummy_data, sizeof(struct ramoops_platform_data)); + &pdata, sizeof(pdata)); if (IS_ERR(dummy)) { pr_info("could not create platform device: %ld\n", PTR_ERR(dummy));